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PR013

March 1994

Technical Bulletin

SelectPress Light Output

This bulletin gives instructions to aid SelectPress users in correcting light printing on pages. This procedure outlines cleaning the printer's Auto-toner sensor, which monitors the amount of toner applied to the drum in the EP cartridge (also known as a Process Unit). If this sensor is dirty, text and graphics can appear lighter than normal, even though there is enough toner in the printer. Proper cleaning of this sensor will result in improved image quality. Note that the print density can normally change depending on the texture and relative humidity of the paper being used. To clean the Auto-toner sensor, follow the directions below, being careful not to touch the green surface of the photo-sensitive drum. If you have any difficulty with this procedure, please contact GCC Technical Support at (781) 276-8620.

Figure 1: Diagram of Auto-toner sensor

The Auto-toner sensor (figure 1) is comprised of a LED emitter that shines an infrared light on the surface of a metal band located on the left side of the EP cartridge's green photo-sensitive drum. This light is reflected and measured by a receptor that sends intensity information to the printer's controlling circuitry. If the emitter or receptor elements are dirty, the proper values will not be indicated and the printer will not apply the correct amount of toner to the drum.

  1. Turn the printer off. Open the top cover and inner cover. Remove the toner and EP cartridge. DO NOT TOUCH THE SURFACE OF THE GREEN DRUM OR EXPOSE IT TO DIRECT SUNLIGHT.
  2. The Auto-toner sensor is located on the inner left side of the area the EP cartridge slides into (see figure 1). Insert a cotton swab into the opening on the underside of the black plastic housing (figure 2). There is a slotted metal shaft which partially blocks the entrance to the opening. You will need to manuver the swab around this shaft. Make sure you insert the swab into both channels inside the opening, to clean both the emitter and receptor (figure 3). Figure 2: Auto-sensor housing
    Figure 3: Cleaning the Emitter Figure 4: Cleaning the EP
  3. You must also clean the metal band (figure 4) on the left end of the EP cartridge's drum. Use a dry cloth to clean this surface. Do not touch the metal band with your hand. Do not attempt to clean any toner from the surface of the green drum.
  4. Reinstall the EP cartridge and toner cartridge, and close the printer's covers.
This completes the cleaning procedure for the Auto-toner sensor. Turn the printer on and print a few pages to confirm that the cleaning was successful and that it is allowing more toner to be fed to the drum. If the print quality improves but does not return to its normal level, perform the cleaning procedure again. If the problem still persists, contact GCC Technical Support at (781) 276-8620.
Rev: 6/12/96




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